PRT/5-FU前药转换酶系统对小鼠胃癌治疗的实验研究

Gene therapy for murine gastric carcinoma with UPRT/5-FU enzyme/prodrug system in vitro and in vivo

目的 探讨UPRT/ 5 FU前药转换酶系统对小鼠胃癌细胞MFC的杀伤效应。方法 采用PCR技术从大肠杆菌K12基因组中扩增UPRT基因 ,并构建pLXSN逆转录病毒表达载体 ,进一步转染MFC细胞。采用MTT法检测转导UPRT基因前后 ,MFC对 5 FU的敏感性的变化。建立 6 15小鼠胃癌皮下移植瘤模型 ,腹腔内给于 5 FU ,观察治疗效果。结果 体外MTT法检测结果显示 ,转导UPRT基因后可使MFC对 5 FU的敏感性提高约 17.2 6倍。动物实验的结果表明 ,转导UPRT基因不影响MFC的致瘤性 ;经 5 FU治疗后 ,转UPRT基因的肿瘤 ,生长明显受抑 (P <0 .0 0 0 5 ) ,抑瘤率为 89.6 2 %。结论 UPRT基因修饰小鼠胃癌细胞株MFC ,能明显提高MFC对 5 FU杀伤的敏感性 ,增强 5 FU的抗瘤效应。

Objective To investigate the killing effect of UPRT/5-FU Enzyme/Prodrug System on murine gastric cancer. Methods The UPRT gene encoding uracil phosphoribosyltransferase was amplified from E. Coli K12 genome. The nucleotide sequence of UPRT gene was sequenced and subcloned into retrovirus expression vector pLXSN, The Recombinant retrovirus was packaged and used further to infect MFC. The sensitivity of MFC transduced with UPRT gene to 5-FU in vitro and in vivo was detected. Results The 5-FU sensitivity in MFC transduced with the UPRT gene increased 17.26-fold as compared with the control cells. Transdution of UPRT gene into MFC did not influence its immunogenicity and tumorigenicity. When the MFC/UPRT cells were implanted subcutaneously into 615 mice and followed by the administration of 5-FU (10mg/kg) intraperitoneally significant inhibition of tumor growth was observed( P <0.0005) with an inhibition rate of 89.62%. Conclusion Transduction of UPRT gene can render the murine gastric cancer cell line MFC be more sensitive to low concentration of 5-FU and improve significantly the antitumor effect of 5-FU both in vitro and in vivo.